Assickctob



Feb. 15, 1927.

W. A. DOBLE OIL BIURNER IGNITION DEVICE Filed May 20. 1924 /N VEN TOR @IHM f7. QBLE,4 ar M /l nj Y/Z/Ma/ AmBNE YS.

Patented Feb. 15, 1927.

'WILLIAM A. DOBLE, or 'sia'N FRANCISCO, CALIFORNIA, {assietion tro nonnn nazenn- Tomas, or sAN rRA'NoI'sco, CALIFORNIa A oonronArIoN or CALIFORNIA.

OIL-BURNER IGNITION DEVICE.

AApplication filed 4May 20, 1924. SerialfNo. 714,552.

The invention relates to a device tor igniting the combustible mixture produced by a liquid fuel burner.

An object ot `the invention is to provide ya pilot light which will not be extinguished -by the blast of combustible mixture discharged by the burner.

Another object ot the invention ris to provide a 'gas burning pilot 'light which will `not be extinguished by an abrupt increase in the amount of gas delivered to the pilot light burner.

Another object oi. theinvention is to provide 'a pilot light which is shielded from the draft occurring -in the combustionchamber ot Ythe furnace, so that a very small -lame may be normally maintained at the pilot.

The invention possesses other advantageous `features, some 'ot' which, with the lforegoing, 'will be set `forth vat length in the following description, where l shall outline in full that `form oi' my linvention which I have selected 'for illustration in the drawings accompanyingand forming ypart of the present specification. In said drawings 'I have shown one torm ot 'device embodying my invention, but it is to be understood that I do not limit myself to such `form, since the invention, Aas set forth in the claim, maybe embodied in a plurality ot' forms.

Referringto said drawings:

Figure 1 is a horizontal section through a furnace showing the device of my invention arranged in its environments.

Figure 2 is a vertical longitudinal section through the device of my invention.

Figure `3 is an end view ot the device of my invention.

Figure 4 is a vertical section through a device for controlling the supply of gas to the pilot light burner.

Oil burners are equipped with pilot lights for igniting the blast ot combustible mixture introduced into the combustion chamber ot a furnace bythe oil burner. The combus tible mixture consists of a mixture of air and atomized liquid fuel. The burner is constructed to produce this mixture and to discharge the mixture in a blast. into the combustion chamber. A gas burning pilot light is arranged adjacent the burner and, in order to ignite the combustible mixture, the supply of gas to the pilot light is increased so that a large flame -from the pilot light burner is ydirected into the blast ot combustible mixture, to ignite the same. N0rmally, the flame at the pilot burner is very small and sometimes it is `blown out by the draft inthe combustion chamberor by the blast Yproduced by the burner. Frequently when the supply ot gas to the .pilot light burner is abruptly and greatly increased to cause the projection ot the igniting iiame into the combustible mixture stream, the speed oIpfthe gas issuing from the small aperture in the pilotlight burner, is suihcient to blow out the iiame. In accordance with my invention, I have provided means for preventing the abrupt increase in the sup- .ply of 'gas from extinguishing the flame and for preventing the draft of air 'or the 'blast in the combustion chamber from extinguishing the small pilot llame.

The supply ofgas to the pilot light burner is usually controlled 'by a solenoid which is arranged in series with a single phase motor `which is used for driving the blower which forms part of the burner. lhen the motor is started, current ows in the starting winding thereof and ythis winding is suitably'conn'ected to a solenoid which operates to o'pen `a valve and permits the abrupt increase in the supply of gas to the pilot light burner. As soon as vthe Vmotor has come 'up to spee'd, the starting winding is out out by fany suitable lmeans and the core 'of the solenoid falls, partially closing -the valve, so that -only sutticient gas is .permitted to -flow to maintain a very small pilot light. In Figure 4 I have shown one form of valve for accomplishing this result. The gas enters the valve through the pipe 3 and discharges through the pipe 4 to the pilot light burner 5. Arranged in the valve body 6 is al piston valve 7 having a narrow portion 8, which, when it is in registry with the conduits 3 and 4, permits a large amount of gas to flow through the valve. This narrow portion 8 of the valve is normally disposed out of registry with the conduits 3 and 4 and that portion of the valve which is normally disposed between the conduits is formed to permit the passage of a small amount of gas only. Secured to the valve 7 is a core 9 which is associated with a solenoid 12, which is connected through brushes 43 with the starting winding 14 of the motor. l/Vhen the motor is started, a large current passes through the solenoid 12, raising the core 9 and consequently permitting a large amount of gas to pass to the pilot light burner. The movement of the core 9 is abrupt and consequently the increase of the flow of gas to the pilot light burner is abrupt. Secured to the lower end of the valve is a piston 13 which is disposed in a dash pot ll which is filled with liquid. The piston 13 is provided with an aperture 15 controlled by a flap *alve 1G so that upward movement of the piston is not rctarded to any considerable extent by the liquid in the dash pot. The upper and lower portions of the dash pot are connected by a by-pass conduit 17, the area of which is controlled by a screw 18 to control the rate at which liquid flows through the by-pass. When the motor has reached the desired speed, the brushes 43 are removed from the commutator by a centrifugal device or other Well known means cutting off the flow of current to the solenoid and permitting the valve 7 to move downward. This downward movement is regulated by the passage of liquid through the by-pass conduit 17, so that the large ignition flame will persist for a sufficient time to ignite the combustible mixture being introducedl into the furnace. When the motor has come up to speed, the starting winding 14 is cut out and the current passes through the running winding 19 which is usually of the squirrel cage type. The motor 21 is employed for driving the blower and the liquid fuel atomizing means, so that when the motor is started the large igniting flame is produced.

rlhe pilot light burner 5 has usually heretofore consisted of the bare burner tip 5 extending into the combustion chamber, so that it was exposed to the 'draft therein and so that it projected la pencil of flame into the combustible mixture. I have found that the rapid increase in the supply of gas to this burner frequently resulted in blowing out the llame and I have provided means for preventing this action and also for preventing the blast of combustible mixture or the draft in the combustion chamber from blowing out the pilot light.

In accordance with .my invention, I have arranged a shield or burner tip 22 surrounding the pilot light burner 5 so that when the pilot light consists of a small flame, it burns within the tip 22. This tip 22 is suitably supported with respect to the pilot light burner 5 and is provided with apertures Q3- Ql, to permit the introduction of air into the tip for the purpose of supporting combustion. it its discharge end, the tip is preferably flattened and provided with an elongated narrow slot 25 extending across the front face of the tip and preferably disposed horizontally. lVhen the supply of gas to the burner is abruptly increased, the gas tends to bank up or produce a back pressure within the tip 22, thus preventing the llame from being blown out by the high velocity of the gas issuing from the burner. The flame 'discharging from the aperture 25 is wide and flaring and produces a positive and mmediate ignition of the blast of combustible mixture discharged by the burner. The tip or shell 22 is preferably screwed into a socket 26 which seats in the wall of the furnace and through which the pilot light burner 5 extends. The aperture 2st in the shell is preferably formed directly over the end of the pilot light burner, so that a sufficient quantity of air is induced through this aperture when the amount of gas discharging from the burner 5 is increased. The apertures 23 and 24e are preferably arranged on the top and bottom surfaces of the shell Q2, so that the small flame 27 on the end of the burner is shielded against the draft in the combustion chamber.

I claim:

In a horizontally disposed burner, a shield forming a chamber, and a fuel supply pipe terminating in said chamber, said shield being provided with an opening below the end of said supply pipe and an opening above the end of said supply pipe whereby a vertical draft is permitted thru said chamber.

In testimony whereof, I have hereunto set my hand.

WILLIAM A. DOBLE. 

